Currently it is known to deposit the spacer frame or the spacer profile on a glass pane and then couple the assembly to a second glass pane and seal it so as to constitute the so-called insulating glazing unit. The operation can also be repeated in order to obtain an insulating glazing unit constituted by three glass panes and two spacer profiles or frames, as well as n glass panes and n−1 spacer profiles or frames.
In order to better understand the configuration of the glass pane, not so much in its possible isolated use but above all in its use in combination with other components, in particular the spacer profile or frame for constituting the so-called insulating glazing unit, some concepts which relate to said intermediate components, i.e., the glass pane and the spacer profile or frame and the end product, i.e., the insulating glazing unit, are summarized hereinafter, under the assumption that the subsequent use of the insulating glazing unit, i.e., as a component of a door or window, is known. To allow efficient description, the end product is first described and then its components.
The insulating glazing unit is constituted by composing two or more glass panes, which are separated by one or more spacer frames which are generally metallic, for example made of aluminum but also made of rigid plastic material, and are hollow and finely perforated on the face directed toward the inside. The spacer frames contain, in their hollow part, hygroscopic material which is intended to trap the moisture that inevitably is diffused in the air when the insulating glazing unit is being manufactured, as well as the moisture which might penetrate subsequently in the case of less than perfect tightness of the assembly that constitutes the insulating glazing unit. The air space (or spaces) delimited by the glass pane or panes can contain air or gas or mixtures of gases which give the insulating glazing unit particular properties, for example heat insulation and/or soundproofing properties. Recently, the use of a so-called spacer profile has become widespread; said spacer profile has a substantially rectangular cross-section and is made of expanded synthetic material (by way of non-limiting example, silicone and EPDM), which incorporates within its mass the hygroscopic material.
This type of spacer profile, and in particular its sealing requirements with respect to the glass panes coupled thereto, is the subject of the present patent application.
The coupling between the glass panes and the frame (or frames), in the traditional case with the frame 1, is obtained by means of two levels of sealing: the first one being intended to provide tightness and an initial bonding between said components and involving the lateral surfaces of the frame and the portions of the adjacent glass panes; and the second one, having the function of providing permanent cohesion among the components and mechanical resistance of the joint between them, and involving the compartment constituted by the outer surface of the frame and by the faces of the glass panes in the region between the outer surface of the frame and the rim thereof (see FIGS. 1A-1E).
Such innovative profile has two advantages: the low coefficient of heat transmission by conduction and the first level of bonding with the glass, said bond being instantaneous since may be entrusted to the acrylic adhesive and not to the traditional thermoplastic sealant, the latter being subject to flow until the second sealant, described hereinafter, catalyzes.
The first sealing can be performed, for example, by means of polyisobutyl sealant (abbreviated as PIB), with heating.
The second sealing can be typically performed by using the following range of products:
cold two-component polysulfide sealant (PS)
cold two-component polyurethane sealant (PU)
cold two-component silicone sealant (SI)
cold single-component polysulfide sealant (PS)
cold single-component polyurethane sealant (PU)
cold single-component silicone sealant (SI)
and, rarely, hot catalyzing butyl sealant (HM).
The respective abbreviations/acronyms are provided in brackets and are the same for the two-component or single-component versions, since this aspect is irrelevant in terms of the description of the invention. The term “cold” references ambient temperature.
In the case of a spacer profile 1′, 1″ made of expanded synthetic material, the first level of sealing is replaced by an adhesive, for example an acrylic adhesive, although it does not have tightness functions (which are transferred to the next levels), which is already spread onto the lateral faces of the spacer profile 1′, 1″ and covered on said faces by protective films which must be removed before use. The next sealing levels can be summarized in the following cases (for the sake of brevity, the abbreviations cited above are used):
only HM; PIB+PS; PIB+PU; PIB+SI.
It should be noted that the final sealing with silicone is required for so-called structural uses, i.e., uses in which the final sealant is entrusted with the tough and resilient retention of the pane which faces outward. This sealant, being exposed to ultraviolet radiation, can only be made of silicone.
The above is provided in order to present types of products and sectors of use which are expanding increasingly: the products (insulating glazing unit) because they have the spacer frame made of a material with a low heat transmission coefficient, and the sector because it comprises the sector of architectural structures in which the glazing unit is no longer just an infilling material but assumes structural functions so as to form so-called curtain walling or structural glazing.
Generally, the glass panes 2 used in the composition of the insulating glazing unit 3 can have different shapes depending on their use: for example, the outer glass pane (understood with respect to the inner space of a building) can be normal or reflective (in order to limit thermal input during summer months) or laminated/armored (for intrusion/vandalism prevention functions) or laminated/tempered (for security functions) or combined (for example reflective and laminated to achieve a combination of properties), the inner pane (understood with respect to the inner space of a building), can be normal or of the low-emissivity type (in order to limit heat dispersion during winter months) or laminated/tempered (for security functions) or combined (for example low-emissivity and laminated in order to obtain a combination of properties).
A manufacturing line for obtaining the insulating glazing unit product 3 requires many processes in sequence, which are preferably automatic, and in particular comprises the operations of applying the spacer frame 1 or the spacer profile 1′, 1″ and sealing.
Processes for manufacturing the insulating glazing unit 3, each requiring a corresponding and particular machine to be arranged in series with respect to the other complementary ones, are, by way of nonlimiting example and at the same time not entirely necessary, the following:
EDGING on the peripheral face of the pane to remove any coatings, in order to allow and maintain over time the bonding of the sealants and, in the case of the subject of the present invention, both the bonding of the adhesive and the bonding of the sealants;
GRINDING (so-called “arrissing”) of the sharp arrises of the pane in order to eliminate edge defects introduced by cutting the panes into formats and reduce the risk of injury in subsequent handling of the glass pane and of the insulating glazing unit;
WASHING of the individual glass panes, with inner pane/outer pane alternation (the orientation being the one defined above);
APPLICATION OF THE SPACER FRAME: the previously manufactured frame, filled with hygroscopic material and covered on its lateral faces with a thermoplastic sealant (PIB), which has sealing functions, in machines which are external to the production line of the insulating glazing unit 3, is applied to one of the glass panes which constitutes the insulating glazing unit 3 in an appropriately provided station of the production line of the insulating glazing unit 3; as an alternative and more effectively, a continuous strip of spacer profile made of expanded synthetic material 1′, 1″ is unwound from a reel and applied automatically to one of the two panes until it forms a closed frame which is built directly in adhesion against the glass pane, after removing the protective films, and on the same production line as the insulating glazing unit 3;
MATING AND PRESSING of the assembly constituted by the glass panes and the frame (or frames);
FILLING WITH GAS of the air space (or spaces) thus obtained;
SECOND SEALING (and optionally THIRD SEALING).
The processes set forth above can be performed by a respective machine automatically or semiautomatically.
The background art related to such automatic sealing machines is constituted typically by the following documents:
EP 0 471 247 A1
EP 0 423 106 A1
EP 1 528 214 A1
which teach nothing regarding versatility features of the machines disclosed, such as to equally work with at least two distinct products, but rather propose an opposite teaching.
These documents and the corresponding manufactured machines in fact respectively teach only the following:
EP 0 471 247 A1: to feed a combination of two components, dosed individually, of a two-component product either to the extrusion head of the automatic machine or to a manual device in which mixing and extrusion occur;
EP 0 423 106 A1: a method for controlling the dosage of the sealant, performed also by varying the speed of the elements for moving the insulating glazing unit and the extrusion head; and a possibility to feed the sealant, but always the same sealant, to more than one extrusion nozzle;
EP 1 528 214 A1: feeding the PIB onto the sides of the spacer made of expanded synthetic material before applying it to the glass pane.
Therefore, these teachings are rather opposite, i.e., they prospect a plurality of extrusion user devices which all use the same product.
Other background art has been developed after that of the above mentioned documents that consists of many other documents that are less pertinent than EP 0 471 247 A1.
Background art resides in manufactured machines produced by the inventors as the present application, in which it is possible to convert between two of the three products PS, PU, SI (all of which operate at ambient temperature) but it is always necessary to replace a substantial fraction of the components for feeding the sealant into the extrusion head region, therefore entailing modification times which are not consistent with the demand for prompt versatility that is currently required.
The typical production of an insulating glazing unit manufacturer (regardless of whether the unit has a traditional spacer frame made of aluminum profile or an innovative one made of expanded synthetic material) in fact consists of 80% of the traditional type of insulating glazing unit and 20% of the structural insulating glazing unit type. With such proportions, having several lines for the production of insulating glazing units, each dedicated to one type of product, is not justified, since the proportion which saturates its use would be three lines for traditional production and one line for structural production. In view of the productivity of each line of approximately 500 units in 8 working hours, this configuration would be applicable only for manufacturers which have a production of at least 2000 units in 8 working hours, but typical average production is instead 400 units in 8 hours; hence the need to have an automatic machine which is versatile and therefore allows all of the production line of the insulating glazing unit 3 to also be promptly versatile.
The most important problems of the background art described above are therefore the following:
the need to dedicate a machine to the sealing of the hot PIB type, a second machine for the hot HM product, and a third machine for the cold SI or PU or PS product;
the complexity of the operation for replacing the components for feeding the sealant in the region of the extrusion head in the case of a version of a machine which is potentially preset to replace the circuits;
the excessive use of time for this operation.